1. Field of the Invention
Various succinic acid derivatives are already known as anticorrosion agents. Thus reaction products of alkenylsuccinic anhydrides with aminocarboxylic acids of the formula ##STR2## are described, for example, in U.S. Pat. No. 3,903,005.
2. Description of Related Art
It is already known from German Pat. No. 917,027 to add alkylsuccinic acids to hydrocarbon oils as a rust inhibitor. In media containing water, however, alkylsuccinic acids have the disadvantage of forming insoluble alkaline earth metal salts with the constituents of the water causing hardness and are thus precipitated, so that they are unsuitable for use as water-soluble anticorrosion agents.
Amine salts of amide acids which are obtained by reacting succinic or maleic anhydride with primary alkylamines containing 4-30 carbon atoms in the alkyl chain and subsequently neutralizing the product with such amines are also known from German Auslegeschrift No. 1,149,843 as lubricant or fuel additives having a rust-preventive action. However, these compounds are not oil-soluble and in most cases are not water-soluble; insofar as they are water-soluble, they develop foam much too powerfully or, if they have a low foaming action, they lose a large part of their anti-corrosion effect.